topic Re: S32K1XX FLEXCAN in S32K

S32K1XX FLEXCAN

PINKMAN — Sat, 14 Sep 2024 06:56:24 GMT

hello ,experts:

We know FLEXCAN support CAN receive by MB and RXFIFO

I have a question that when i config Message received in RXFIFO mode with interrupt ,the rxFIFO engine occupied 0-5MB,and i set 8 Rx FIFO Filters which occupied 2MB

so the first 8 MB is used for rxFIFO engine and Filters element. there are 24 MB (S32K116)left,.

It is clear that i can config any MB in the range of left MB for transmit ,BUT I wonder that if i can set a MB used for Receive, Even i have used RX FIFO.

if yes ? can you share a demo for me ?

if no , that means the MB after FIFO could only used for transmit MB ?

Re: S32K1XX FLEXCAN

PetrS — Mon, 16 Sep 2024 08:54:47 GMT

Hi,

rest of available MBs can be set for both TX and/or RX operation.
Some SDK based example is posted at https://community.nxp.com/t5/S32K-Knowledge-Base/Example-S32K144-FlexCAN-RXFIFO-DMA-S32DS-ARM-2018-R1/ta-p/1120014
Hope it helps.

BR, Petr

Re: S32K1XX FLEXCAN

PINKMAN — Mon, 16 Sep 2024 15:22:57 GMT

thank you ! in fact, if i use RXFIFO meanwhile i also set a MB for RX, if the message passed the filter element ,so the MB for RX will not be used ?

Re: S32K1XX FLEXCAN

PetrS — Tue, 17 Sep 2024 07:24:30 GMT

Hi,

depends on the setting, but if RXFIFO is set to be searched first and the Rx FIFO is a matched structure and is free-to-receive, then the Rx FIFO is the matching winner regardless of the scan for MBs. Then at the end of matching process the message is moved-in to RXFIFO.
I can recommend to read chapters Receive Process and Matching Process of the device RM.

BR, Petr

Re: S32K1XX FLEXCAN

PINKMAN — Tue, 17 Sep 2024 11:56:30 GMT

非常感谢

Re: S32K1XX FLEXCAN

PINKMAN — Wed, 18 Sep 2024 02:57:18 GMT

i'm sorry, there is still a question that if i use RXFIFO, i can only set mask with FLEXCAN_RX_MASK_INDIVIDUAL ? which means only use RXIMR and RXFGMASK to config filter items and other MBs. uder this condition(use RXFIFO),i think use RXMGMASK, RX14MASK, RX15MASK is a wrong configration maybe?

Re: S32K1XX FLEXCAN

PetrS — Wed, 18 Sep 2024 10:36:04 GMT

Hi,

up to 32 elements of the filter table are individually affected by the Individual Mask
Registers (RXIMRx), according to the setting of CTRL2[RFFN], if individual mask scheme is used (IMRQ=1). If the IRMQ bit is negated, then the FIFO filter table is affected by RXFGMASK only and RXMGMASK, RX14MASK, RX15MASK are used for rest of MBs.

BR, Petr

Re: S32K1XX FLEXCAN

PINKMAN — Wed, 18 Sep 2024 13:01:51 GMT

OK ,I GOT IT.NB! THANKS